A pulsed Raman spectrometer, utilizing an N2 pump, will be employed to examine pre-resonance Raman spectra of aromatic amino acids. The influence of small molecule binding on Raman-active modes of the residues will be examined with horseradish peroxidase, and metmyoglobin. Excitation profiles of O-450CAM/ox low-frequency vibrations will be used to locate the S negative ion yields Fe(III) transition. A computer program for implementing the semi-empirical X alpha theory of electronic states will be used to examine the location of charge-transfer states in axially bound hemisphere and charge-density alterations during dioxygen binding. BIBLIOGRAPHIC REFERENCES: J. Shelnutt, D. O'Shea, N-T. Yu, L.D. Cheung, and R.H. Felton. "Resonance Ramam Spectra of Mn(III) Etioporphyrin I", J. Chem. Phys., 64, 1156 (1976). H. Sambe and R.H. Felton, "Empirical Regularities of Atomic Ionization Potentials", Chem. Phys., 13, 299 (1976).